Particle counter with advanced features

ABSTRACT

An airborne or liquid particle sensor with a number of advanced features is disclosed. The sensor includes an output channel generating an electrical signal for a particle passing through the sensor, where the electrical signal includes information related to the pulse. The information is processed by the sensor to determine a value that indicates a more accurate particle mass for a sample period than the average mass.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/701,485 filed on Apr. 30, 2015, titled PARTICLE COUNTER WITH ADVANCEDFEATURES by inventors David PARISEAU, with claims priority to U.S.Provisional Application Ser. No. 61/986,532 filed on Apr. 30, 2014,titled PARTICLE COUNTER WITH ADVANCED FEATURES by inventors DavidPARISEAU, the entire disclosures of which are hereby incorporated hereinby reference.

This application is related to and incorporates by reference: U.S.Non-Provisional application Ser. No. 14/214,899, filed herewith on Mar.15, 2014, titled PARTICLE COUNTER WITH INTEGRATED BOOTLOADER by inventorDavid Pariseau; U.S. Non-Provisional application Ser. No. 14/214,870,filed herewith on Mar. 15, 2014, titled PERSONAL AIR QUALITY MONITORINGSYSTEM by inventors David Pariseau and Adam Giandomenico; U.S.Non-Provisional application Ser. No. 14/214,903, filed herewith on Mar.15, 2014, titled MIXED-MODE PHOTO-AMPLIFIER FOR PARTICLE COUNTER byinventors David Pariseau and Ivan Horban; U.S. Non-Provisionalapplication Ser. No. 14/214,876, filed herewith on Mar. 15, 2014, titledMULTIPLE PARTICLE SENSORS IN A PARTICLE COUNTER by inventor DavidPariseau; U.S. Non-Provisional application Ser. No. 14/214,889, filedherewith on Mar. 15, 2014, titled INTELLIGENT MODULES IN A PARTICLECOUNTER by inventor David Pariseau; U.S. Non-Provisional applicationSer. No. 14/214,895, filed herewith on Mar. 15, 2014, titled PULSE SCOPEFOR PARTICLE COUNTER by inventor David Pariseau; and U.S.Non-Provisional application Ser. No. 14/214,907, filed herewith on Mar.15, 2014, titled PULSE DISCRIMINATOR FOR PARTICLE COUNTER by inventorsDavid Pariseau and Ivan Horban, the entire disclosures of which arehereby incorporated herein by reference.

BACKGROUND

Particle counters have been used for decades in manufacturing orindustrial applications to measure particulate quantities in air, gasesor liquids. Typically such counters also group particulates by size.These size channels vary by application and often by instrument. Aparticle counter has at least one size channel and popular counters canhave 6 or more channels. Typically these size channels discriminatepulses based on the pulse height of the incoming signal, which is ameasure of the light blocked or scattered as particles interrupt a lightbeam (typically a laser). These counts are then often displayed on alocal display as differential counts (particles for a given sizechannel) or cumulative counts for this size channel and all largerchannels. The counts are typically logged in some local memory and canalso be communicated via some external interface to facility monitoringsystems, or remote computers or devices.

SUMMARY

In accordance with the aspects of the invention, a system and a methodare disclosed that enhance the functionality of traditional particlesensors or counters for airborne and liquid particles. The embodimentsset forth, in accordance with the aspects of the invention, extend thefunctionality of traditional particle counters by adding advancedfeatures and functions. These features and functions provide enhancefunctionality, which adds value to these instruments and allows them toprovide both new information, and to process existing information inorder to make it more useful and accessible to users. This addssignificant value to standard instrumentation.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description is directed to certain sampleembodiments. However, the disclosure can be embodied in a multitude ofdifferent ways as defined and covered by the claims. In thisdescription, reference is made to the drawings wherein like parts aredesignated with like numerals throughout.

FIG. 1 illustrates a pulse output of a particle sensor in accordancewith the various aspects of the invention.

FIG. 2 is a particle counting system or instrument in accordance withthe various aspects of the invention.

FIG. 3 is a particle counting system in accordance with the variousaspects of the invention.

FIG. 4 is a graph illustrating counts over a period of time inaccordance with the various aspects of the invention.

FIG. 5 is a graph illustration of the counts in accordance with thevarious aspects of the invention.

FIG. 6 is a display for presenting the data in real-time in accordancewith the various aspects of the invention.

FIG. 7 is a particle counter system in accordance with the variousaspects of the invention.

DETAILED DESCRIPTION

In accordance with the invention, it should be observed that theembodiments reside primarily in combinations of method step andapparatus components related to facilitating the invention. Accordinglythe components and method steps have been represented where appropriateby conventional symbols in the drawing showing only those specificdetails that are pertinent to understanding the embodiments of theinvention so as not to obscure the disclosure with details that will bereadily apparent to those of ordinary skill in the art having thebenefit of the description herein.

Unless defined otherwise, all terms used herein have the same meaning ascommonly understood by one of ordinary skill in the art to which thisinvention belongs. Any methods and systems, similar or equivalent tothose described herein, can also be used in the practice of theinvention. Representative illustrative methods and embodiments ofsystems are also described in accordance with the aspects of theinvention.

It is noted that, as used in this description, the singular forms “a,”“an” and “the” include plural referents unless the context clearlydictates otherwise. Reference throughout this specification to “anaspect,” “one aspect,” “various aspects,” “another aspect,” “oneembodiment,” “an embodiment,” “certain embodiment,” or similar languagemeans that a particular aspect, feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the invention. Thus, appearances of the phrases “in oneembodiment,” “in at least one embodiment,” “in an embodiment,” “incertain embodiments,” and similar language throughout this specificationmay, but do not necessarily, all refer to the same embodiment.

Referring now to FIG. 1, in accordance with various aspects of theinvention, an example of a pulse, which is an example of an output by aparticle sensor (typically a photo-detector and amplifier) created by aparticulate passing through a light beam (typically a created by alaser). The pulse depicts the voltage output of an amplifier over time,though it could be transmitted in a variety of other means (for examplecurrent pulse over time).

Pulses are typically qualified by some baseline threshold to allow fordiscrimination of valid pulses from noise. Valid pulses would then be,in accordance with some aspects of the invention, those signals abovethis baseline threshold. Once a pulse crosses such a threshold 110 it issized by channel typically based on the peak amplitude of the pulse(though in some cases pulse-width might also be a factor, as in somediscriminators designed by Particles Plus, Inc.). In the example in FIG.1, the particulate pulses 101,102 would both be binned in an A channel111 and a B channel 112, but would not be binned in a C channel 113,since the peak amplitude of these particulate pulses 101 and 102 doesnot cross the threshold for the C channel 113. In this example, the massof particulates in the B channel 112 would include all particles withpeaks between the B channel's 112 threshold and the C channel's 113threshold. The amount of light scattered by the two pulses 10 and 102are substantially different. For the purposes of this graphic, bothpulses are shown overlaid on each other, but in reality they would beseparated in time.

True Mass Calculation

Typically when estimating total particulate mass, particle counters takethe number of counts in each size (herein size refers to a range)channel and then the counter calculates an average mass for theparticles in this channel based on an average size estimated at the sizeof particles in the middle of that channel, for example if there was 0.3um channel followed by a 0.5 um channel then the average size of the 0.3um channel would be assumed to be 0.4 um (the middle of the 0.3 um or(0.5 um−0.3 um)/2+0.3 um. Of course other methods might be used toarrive at an estimated size, perhaps this parameter might even be madeto be configurable, the key concept is that current generations ofinstruments attempt to attribute a single average size to allparticulates in that channel for the purposes of calculating particlemass.

To estimate the mass of particles in that channel for a given sample thecounter takes the average particle size (discussed above), converts thatsize to volume of material, multiplies this by the expected density ofthat material to arrive at the mass of an average particle for thatchannel and then multiplies it by the number of particles counted duringa sample to arrive at the particle mass for that channel during thatsample. That figure can then be used directly or scaled to some standardvolume to infer what the particle mass for a standard volume of air ofthis particle size would be based on this representative sample,Multiple channels could be added together to give a sense oftotal-particle-mass for the instrument's entire range or some subsetthereof,

Theses masses are then displayed either as a mass per channel or thetotal mass for all the channels. Since no information on actual particlesizes is retained in the counter, the estimated average size ofparticles in a channel can lead to potentially large errors in estimatedmass versus the actual mass, when the actual average size differs fromthe estimated average size.

To refine this estimate, one can factor in the index of refractivity,the density of particulates, even some assumed geometry for theparticles. This helps to some extent, if data associated with thesefactors for the particulates being counted are available. However, itdoesn't address the issue that particulates are all grouped in a singlechannel and an average of the mass of particles in that channel has tosomehow choose a single value, which may also be represented in a range-to describe this population of particulates.

Typically when particulates are added to a particular channel's counterthe detailed information on that particulate is lost. If however, themass of the particulate is calculated during the acquisition of thatparticle and transmitted as an estimate of its actual mass to thechannel manager, then the system can accumulate not only counts(occurrences of particles) but a sum of the estimated masses of eachparticulate as it arrived. This would provide a far more accuratemeasure of mass than averaging an entire channel could provide.

In accordance with some aspects of the invention, to derive a betterestimate of mass, the system would integrate the area under a pulsecurve for the duration of the pulse above the pulse threshold. Byintegrating that entire area, the system would have a more accuratemeasure of the actual light energy scattered by the particulate as theparticles transited the beam. This would require many consecutivevoltage measurements of the pulse, with each of these summed to providean overall measurement of the area.

In accordance with various aspects of the invention, to derive anestimate of the mass, the system simply measures the pulsepeak—height—and the pulse width (in accordance with one aspect, it wouldbe done at the pulse threshold) and multiply the two to arrive at a 2Drepresentation of the area. This may be less accurate. Thus, inaccordance with some aspects of the invention, a correction factor isapplied to this measurement to account for the expected shape of such apulse. This, in accordance with various aspects of the invention, isbased either on a theoretically calculated or an empirically derivedformula. This would allow the system to quickly derive an estimated massfor each particle as it arrived. If these “areas” were summed andcommunicated along with the counts for each channel, then the systemcould arrive at a more accurate measure of total mass.

In accordance with aspects of the invention, the mass of the particles,in a given channel, is accumulated during the sample by calculating orestimating the actual size of each particle as it is processed withthese values being summed together to provide a more accurate estimateof the total particle mass than is traditionally seen with an arithmeticaverage based on the total particles counted times an estimated averagesize.

Channel Synchronization

Errors often accrue in a counter when attempting to synchronize theaccumulation of counts from various channels over time. A controllermanaging such is burdened with many other tasks. As such there are oftenlatencies in channel management which can entail reading peak pulsesvoltages or reading external channel counters (in the case of wrappingof such counters these might require several reads). All of thistypically occurs linearly and, as such, small timing errors can occurand accumulate that can sometimes skew certain results or values. Theseare typically small variations and are largely ignored.

However, if a system is implemented with a fast pulse-processingparallel front-end (for example, like with an FPGA) then many of theseerrors can be eliminated. The front-end can process each pulse in andmanage the counters in parallel, and all of the data can be latched in asingle operation (likely at the request of the main controller). In thisway, when requested, the front-end can latch all of the counterssimultaneously, as well as the accumulated mass (if available, asoutline above), as well as the elapsed time since the last latch, etc.In that way all of the timing issues inherent in a single controllerimplementation are removed since the data arrives all synchronized andwith an accurate elapsed time so that calculations based on these valueswill have increased accuracy.

Referring now to FIG. 2, a system is represented in accordance with theaspects of the invention. The system includes a particle sensor 200. Theparticle sensor 200 converts incoming particulates to electrical pulses.A pulse processing front-end 203, which could easily be implemented inan FPGA (as described above) or even with discrete logic, a DSP, or afast, dedicated controller, manages the processing of those pulses. Thepulse processing front-end 203 would set at least one threshold for atleast one comparator 201 and get an estimate of pulse width by recordingthe time for pulses above the threshold.

In accordance with other aspects and embodiments of the invention, apeak-detector and analog-to-digital converter 202 would be setup tomeasure an accurate peak height for each pulse, and combined with thepulse width for that pulse (based on the comparator 201 output) toarrive at an estimated pulse area representing the amount of lightscattered by the particle and hence yielding a representation of themass for that pulse. These pulse masses would be summed for the sampleand reported along with the traditional channel counts.

The pulse-processing front-end 203 would be connected to an instrumentcontroller 205, which would manage traditional functions like displayinginformation on a display 208. The display 208, in accordance withvarious aspects of the invention, is an LCD with touchscreen. Thedisplay 208, in accordance with various aspects of the invention, is asingle LED indicating that particle counts are above some predeterminedor configurable threshold. The scope of the invention is not limited bythe type of display. The instrument controller 205 would also allow forthe information to be logged to memory 207, either volatile ornon-volatile or both, and would also allow for communication, through acommunication module or unit 206, with external systems.

Sleep Between Samples

In accordance with the various aspects of the invention, the particlecounters implement a concept referred to as locations and recipes, orsome variant thereof. These allow users to collect air (or liquid)samples according to some pre-arranged parameters and schedule. Forexample, a unit might sample differently in different locations (more orless time) depending on these pre-configured requirements. In some casesan instrument might be placed, left, or unattended for an extendedperiod of time and setup to perform periodic sampling for laterretrieval or analysis (or for remote analysis).

If there is local power (plug-in or some similar outlet for powersupply) then having the unit remain continuously power up (or on) istypically not an issue. In the case where the power source is a battery(limited supply of power) or it is a battery operated unit orinstrumentation, this would limit the potential duration that such aninstrument could remain continuously power up to operate, unattended. Inaccordance with various aspects of the invention, a second controller isadded to such the unit or instrument to manage the power and shut theinstrument down between samples, when the delay between such sampling issufficiently long. The power control, through using a sleep or shut downmode, would greatly extended the amount of time such an instrument couldoperate, unattended or independent of the local power source.

The second controller could also provide a persistent memory to storethe present state of the instrument between power cycles, and timekeeping so it could wake-up after the desired delay so the next samplecould be taken. The second controller would communicate the storedinstrument state so the sampling could continue where it was before theinstrument went to sleep or power cycled.

In accordance with some aspects of the invention, both controller can beimplemented on a single controller. In accordance with some aspects ofthe invention, a second controller can be added that is a dedicated topower management. Hence, a lower-power controller can be used and powerto most of the instrument's (or unit's) board can be shut off duringthese deep sleep periods, greatly increasing the life of the battery,which is an on-board battery.

Referring now to FIG. 3, in accordance with aspects of the invention andanother embodiment, a system is shown that includes two controllersconfigured. An instrument controller 301 controls the normal operationof the system or the particle counter, managing the particle sensor 300,which includes in this example all the pulse processing circuitryrequired to process pulses from particulates. The instrument controller301 manages traditional functions like displaying information on sometype of display 304, which might be as sophisticated as an LCD withtouchscreen or as simple as a single LED indicating that particle countsare above some predetermined or configurable threshold.

The instrument controller 301 would also allow for the information to belogged to memory 303, which is either volatile memory or non-volatilememory or both, and would also allow for communication using, acommunication module or unit 302, with external systems. In addition theinstrument controller 301 would also communicate with a power controller310 to ascertain the current power status of the system, for example thestatus of a battery 311, a battery charger 312, or whether AC power 313is present, as well as possibly recovering non-volatile information likea current real-time-clock-calendar (RTCC) 314 values or some otherstored parameters.

In between samples the Instrument controller 301 could request that thePower controller 310 shutdown power to the instrument circuits forexample 300, 301, 302, 303, 304, and itself enter a low-power modemaintaining only the systems necessary for some period of time, thatperiod perhaps a parameter supplied by the instrument controller 301during the sleep request. The Power controller 310 would then complyshutting down power to most of the instrument for some predefined time(or until some other event occurs, for example a button press, insertionof AC power, etc.

Annotations in Recorded Data

Particle counters provide a mechanism to store sample data to a localmemory area. This data can be accessed locally or downloaded to someremote system for more detailed analysis or processing. This datatypically comprises information like the sample date/time, the channelcounts for that sample, the location/recipe information for that sampleand perhaps some environmental information or error/alarm conditions forthe sample.

It is often difficult to remember conditions that were perhaps notableat the time of the sample, but otherwise go unrecorded in the data. Inaccordance with aspects of the invention, annotations are added to thedata either before the fact, during the sample, or after the fact basedon analysis or discussions with technicians or users.

In accordance with aspects of the invention, a text field is added tothe recorded data samples (or as separate records in the log memory) andusers can annotate the data using the text field. These annotationscould be consulted at some later point when looking at the data andwould provide context for the logged data. For example, in the case ofhigh counts, for a particular sample, an annotation for that samplemight record the fact that a door to a clean air was openedinadvertently by someone, or that a defective filter was located, or anynumber such events. In accordance with aspects of the invention, thesenotes could also be made either before the sample, during the sample orbased on discussions or post-mortem after the data was recorded.

In accordance with aspects of the invention, the annotations could alsobe used to store particular tags in the data that could later be used toautomate the preparation of particular reports. Automated reportgenerators could process the data looking for these tags and performcertain actions based on these tags. For example, adding an annotationof <Rm101> to a number of samples could collect all the data from thatannotation until another was encountered and report all this data asseparate samples in a particular report. This could greatly simplifywhat is largely a manual process for many air quality consultants inaggregating sampling data into reports for clients.

Remote Access/Control (Concurrent Users)

In accordance with aspects of the invention, particle counters aredevices that have one main microcontroller in charge of collectingparticulate information, converting the particle counts into variousformats, logging data, displaying information and communicating withexternal devices. For most instruments this consumes the bulk thecontroller's resources and often this means that overall systemresponsiveness is impacted when significant bandwidth is allocated toseveral of these tasks concurrently.

Implementing a particle counting instrument as a distributed system withmultiple controllers sharing the load provides a means of partitioningthe workload in such a way as to improve responsiveness of each sectionof the instrument. It allows the instrument to dedicate resources to theprocessing of particulate data, so that this task can occur unimpededand reliably (which minimizes the chance of particulate informationbeing lost due to interrupt latencies and such). Likewise a dedicatedcontroller managing the user interface and manipulation of the datameans that the user-interface remains responsive and that enhancedgraphical display can be implemented. Finally, with a controllerdedicated to external interfaces the system can ensure that suchinterfaces remain responsive during even high pulse throughput events.

In accordance with aspects of the invention, a distributed system alsooffers means of having multiple concurrent users. For example, a localuser might be sampling data, and manipulating the graphical displayinterface to analyze the incoming data while the data is being sentautomatically to a facility monitoring system, and one or more usersaccess the data via web-browsers remotely. With this architecture alarge number of such interfaces are possible concurrently.

In accordance with aspects of the invention, remote control of theinstrument is possible. In a variety of situations it is desirable to beable to monitor the instrument remotely and control or configure itremotely. Rich external interfaces might allow for users to do such,either by controlling the local display and instrument directly (in thecase where a supervisor might walk a subordinate through setting up aninstrument for a particular task via a remote browser interface, so thatthe subordinate can monitor the changes as they occur). Or, theinstrument could be controlled by the operator from a remote location,in the case of a unit mounted in a fixed location, or left in place toprovide periodic monitoring.

In accordance with aspects of the invention, the remote access featurecan also be used to upgrade instruments or units in the field with newconfigurations or features, without having to open the instrument toaccess the unit's internals.

User-Configurable Instrumentation

Most particle counters are instruments that are configured at thefactory and retain that configuration over their lifetime. A few suchinstruments allow limited upgrades, but these are largely done as afixed upgrade that would apply to an entire family or class of productsand not to a particular instrument.

In accordance with aspects of the invention, significant advantagesaccrue if the individual instruments are upgradeable in the field. Thisallows a manufacturer to offer maintenance subscriptions and upgradepaths for existing instruments, allowing such to be upgradedin-the-field without any removing the instrument from service, ordowntime. In much the same way as computers and phones are now routinelyupgraded, these instruments could upgrade themselves as bug fixes or newreleases to the firmware became available.

In accordance with aspects of the invention, the upgrade might beinitiated by the user rather than automated procedures, so that the usercould choose whether or not to accept such an upgrade. It also allows aninstrument to be purchased with one set of options and features andlater upgraded to add additional options or features. For example, a 3channel instrument with basic graphics and data analysis, could at somelater date be upgraded to a 6 channel instrument with an advancedgraphics package, and external facility monitoring interface. This couldbe done without adding any hardware or returning the unit to thefactory.

In accordance with aspects of the invention, in one embodiment the userwould access the manufacturer's website, and on selecting theirinstrument from a list of registered instruments adjust the feature setor options installed for that instrument purchase the desired upgradesand download them to a local computer from which they'd be installeddirectly to the instrument in question. In accordance with aspects ofthe invention, in another embodiment this all could be accomplisheddirectly from the instrument in question. This capability allows a userto purchase a basic instrument and then to upgrade that instrument astheir needs evolved over time, without being required to purchase anentirely new instrument.

Intelligent Sub-Systems

Typically particle counters have reasonably simple sub-systems. Theseinclude photo-amplifiers, laser controllers, pumps, batteries. Typicallynone of these have any local intelligence (as in microcontrollers oreven memory) and only simple interfaces to the main system. This makesidentification of individual components impossible (a counter cannoteasily determine if a photo-amplifier, or pump has been changed from oneuse to the next). It also complicates troubleshooting instrumentfailures or predicting such ahead of time.

In accordance with aspects of the invention, adding local intelligenceon sub-systems within the counter, the instrument or unit can provideenhanced functionality, reliability and diagnostics. For example eachsub-system could contain model information with detailed operatingparameters for that sub-system, as well as serial number information forthe sub-system in question. This allows an instrument to ensure that thesub-systems in an instrument are the same sub-systems as were usedduring the last calibration (or alert the user to any changes). For someapplications like the pharmaceutical industry such information isimportant as it would eliminate being able to use such an instrument forreporting.

It would also simplify the high-level particle counter implementation.In accordance with aspects of the invention, the module is allowed tomanage the low-level operations. Thus, the instrument can simply providehigh-level direction for the sub-system and leave the implementation ofsuch to the sub-system itself. For example, the counter might requestthat the pump operate at 75.2% of its rated power and adjust this valueup or down as required to achieve a desired flow, rather than having toattempt to control a motor to achieve this. This means that variouspumps could be substituted in an instrument over its lifetime withoutthe main counter firmware having to change to manage a large number ofpumps. It also means that pumps with significantly different flow ratescan be interfaced similarly, without significant changes to theinstrument. In some instrument the flow rate might be 0.1 CFM, in others1 CFM or even 10 CFM without requiring different interfaces even thoughthe pumps themselves and their controllers are vastly different.

In accordance with aspects of the invention, having local control allowsintelligence to be embedded in the sub-systems. That intelligence canprovide real-time control and monitoring of components in the sub-systemas well as providing statistical lifetime information, and performingpredictive analysis. The real-time control we've already discussed, thelifetime statistical information allows a unit track the total hours itsrun, the minimum and maximum and average conditions it encounteredduring its lifetime. A log of any errors encountered over its lifetime,etc. Since it tracking lifetime performance, the system can providewarnings as control parameters approach end-of-life or failureconditions. For example, by tracking current of the pump over its life,the system could provide an early-warning indication of impendingfailure of such before it occurs. This would allow a user to planpreventive maintenance before such causes a removal of service for theinstrument. Furthermore, by tracking operational parameters, the systemmight also be able to determine when an instrument should berecalibrated, using more than simply elapsed time.

The sub-system alerts are based on parameters within the sub-systemitself. These could be adjusted remotely in order to adjust the responseof these systems over time, and to refine their behavior as historicalinformation for these accrues over the product life-cycle and algorithmsrefine these behaviors to render them more accurate and useful.

Advanced Alarming

Most particle counters have reasonably simplistic alarming. Thisnormally consists of a simple alarm threshold for each channel. Once achannel reaches this threshold alarms are asserted. An extension of thisadds alarming to specific recipes. In accordance with aspects of theinvention, alarm thresholds for one sampling setup might differ fromothers. That makes sense since the conditions might well differ as well.In some cases the system is measuring the air in a relatively cleanlocation and would want the alarms for that area to differ thansampling, the system might do in a significantly less clean location.Examples of these might be a gowning room in a cleanroom which is arelatively gray area compared to the highly regulated environment of thecleanroom proper. Many other such examples exist. This allows thesealarms to be defined in this way, so that they take precedence ofchannel alarm thresholds, so that the user doesn't have to adjust thechannel alarms in order to create different alarm thresholds fordifferent “recipes” or location samples. Also, both traditional alarmsand recipe alarms can also be configured with thresholds based on theparticulate mass calculation rather than counts on a specific channel.This allows for capabilities that are not implemented on existinginstruments.

In accordance with aspects of the invention, alarms can be specified forenvironmental conditions (as in temperature or relative humidity), whichextends the capabilities of the instrument for monitoring and reactingto more than just particulates. As other intelligent sensors are addedto the instrument (through an intelligent port) these can also be usedfor alarming. Such sensors include but are not limited to: air velocity,differential pressure, various gas sensors, etc.

Advanced Graphs/Charts

Particle counters typically display counts for a sample period asaccumulating counts over the period in question, either the counts for aspecific channel itself or the sum of counts for that channel and allthe other larger channels. This information is usually displayed as rawcount numbers and it can be difficult to determine trends in such datawhile simply looking at numbers increasing on a display. Displaying thedelta in these counts over a short period (say 1 second) is an attemptto make variations in the data more evident. It's still difficulthowever to visualize either trending changes or periodic changes bylooking at values.

In accordance with aspects of the invention, graphs and charts areparticularly useful for providing visual indications of such trends.Referring now to FIG. 4, a means of visualizing changes in particulatesover time is illustrated, which shows graphing of instrument data. Thesecan be run in real-time on data arriving into the instrument or theymight also be run on data already logged within the instrument. Thebottom axis is time, in seconds. The vertical axis is particle countsfor a particular sample. In this case there is an average of ˜12,000particles/second and, the system can see the variations in this data. Inaccordance with the various aspects of the invention, an advancedinstrument captures data much more quickly and could map this data witha much finer time resolution. That data could then be further analyzedwith any number of techniques or graphs to provide more detailedinformation on the data. For example an FFET (Fast-Fourier-Transform)would provide a frequency analysis of the data and might pinpointcertain frequencies at which particulates are arriving at theinstrument. These frequencies might provide indications as to possiblesources for these particulates.

The instrument could graph from each channel simultaneously, or theinstrument could provide a multi-channel histogram, as shown in FIG. 5,to display relative views of the data for each channel, perhaps with thealarm thresholds coded in a separate color for counts above somepre-defined alarm threshold.

Alternatively this “equalizer” type display could have horizontal barswith the maximums for each channel persistent for some short period(handful of seconds) that way as the bars changed the local maxima couldbe persistent to show local short-term trend information.

Real-Time Meter

Particle counters are typically used to monitor and record particlecounts over time. It can be quite challenging to use them to attempt todiscern the source of particulates. This is often largely because of theway the information is displayed (as cumulative counts, and as numberson the screen which must be interpreted real-time to make decisions asto the likely direction of particulates as the counter is moved about).In accordance with the various aspects of the invention, beeping abovesome threshold, or alarming, to attempt to improve the responsiveness ofthese instruments to particulate sources.

Referring now to FIG. 6, a display is shown, in accordance with thevarious aspects of the invention, for presenting the data in real-timein such a way as to be visually responsive to the present state ofparticles as they arrive into the instrument. This simplifies thetracking of such particles to their source. The display gives a visualindication of 6 channels of data. This particular histogram has a logscale that gives a relative indication of particulate traffic for eachchannel. The Range slider adjusts the sensitivity of the counters, sothat the user can adjust it as the source of the particulates areapproached so the system doesn't saturate the chart. The intention isthat the user adjusts the slider to try and keep the maximum channelnear the middle of the range. This provides strong visual feedback ofthe particulate data in real-time that can be used to facilitatetracking particulates to their source.

In addition to this display, the system can also provide similarfunctionality via audio, either through an on-board audio transducer orexternal headphone or earbud. The instrument could output either a setof pulses indicative of the scale (increasing frequency based on theheight of the selected channel, or a tone with a frequency indicative ofthe height of the selected channel (with a low frequency tone indicatingfewer particles and a higher tone indicating more particles). This wouldallow a user to use this instrument without having to continually lookat the display (in cases where they are looking at potential particulatesources around equipment etc.).

In accordance with aspects of the invention, in order to provide asmoother audio output the rate of change for the audio signal can belimited, such that it provided a more continuous tone with a more slowlyvarying frequency despite what might be dramatically differentvariations in particulate rates.

In accordance with aspects of the invention, a number of differentembodiments are possible for audio. The instrument or unit could bedesigned to have an output like a Geiger counter, with increasing pulserate indicative of the particle volume encountered (at a particularsensitivity). It could also have an output like a metal detector with atone of varying frequency (again based on the present sensitivitysetting).

Pulse Log Buffer

Particle counters process pulses as they arrive. In accordance withaspects of the invention, particle counters measure the pulse height andsometimes the pulse width and then increment the counter for aparticular channel based on one or both of these parameters. Once thisis done detailed information on an individual pulse is discarded.

If this and other parameters, for each pulse, are stored in a pulse logbuffer, it could be used to provide more detailed analysis onparticulates. If the system stored the time of arrival for a pulse, thepulse height, and width, then the system could use this information tocalculate a more accurate mass (as in item 1 above), though this mightbe done in real-time. But, having the data time-stamped would allow usto run more detailed temporal analyses on the data. A more accurate FFTmight reveal patterns in the data, it might identify issues in theairflow (both external and internal to the counter, for example it mightsignal pulsations in the airflow caused by a failing pump).

When particle concentrations are large this might well constitute anenormous amount of data, arriving at a high data rate. Under suchconditions the data needs to be cached quickly in a large memory.Present day FPGAs and SRAM, SDRAM, or DRAM memory chips are particularlysuited to this task. A particular capture profile might also be provided(limiting the data captured based on time, particle size, particle area,or some snapshot after a trigger event (for example capture ‘n’particles when before, during or after a particular particle density isreached).

Sophisticated triggers can limit the data captured and hencepost-capture analysis to events that are particularly of interest orconcern. The intention is to provide features commonly seen on a digitalstorage oscilloscope, as to triggering, capture, and display of thedata. In addition to complex triggers, multiple events could becaptured, averaged, or gleaned for minimum/maximum values to provide anenvelope for the event. The data could be processed locally ordownloaded to a local controller for further processing or display orexported to an external computer for further analysis or manipulation.This functionality also provides the means to potentially improvecalibration of an instrument. If extensive data is captured or collectedduring the calibration process, the a more accurate individual channelcriteria can be derived to arrive at better separation between adjacentchannels, and therefore allow many more discriminated channels within aninstrument.

Instrument Network

In accordance with aspects of the invention, particle counters can beindividual instruments and networked. In accordance with aspects of theinvention, some are networked and connected to facility monitoringsystems or to central networks within a facility. At times instrumentsare networked locally and perhaps connected to external data collectionor display units. In accordance with aspects of the invention,connecting a system with multiple particle counters through a simplehub/switch to a more sophisticated counter with a display allows for avery low-cost system that can be installed simply and provide display,logging and reporting from low-cost particle counters without eachrequiring a display or sophisticated interface. It does so withoutrequiring computers or external monitors be installed and loaded withdata collection and analysis firmware.

In accordance with aspects of the invention, referring to FIG. 7, in oneembodiment is shown with a particle counting instrument 70 is shown withparticle counters 72 (each, in accordance one aspect of the invention,without a display) and an Ethernet network hub or switch 74. Inaccordance with aspects of the invention, the instruments/particlecounters/units communicate via a number of means, some of which includeWiFi, RS-485, RS-232, Zigbee, Bluetooth, or any number of other links.Thus, a small network can easily be formed without requiring externalhardware and software. This significantly lowers the cost and complexityof setting up a small monitoring system in an area. Such a system couldbe used to implement a small monitoring system for a manufacture thathas only a small clean area, perhaps in final assembly or the like.

In accordance with aspects of the invention, it also provides a means ofdeploying such a system for troubleshooting in a large factory. Forexample in a large pharmaceutical factory, or when qualifying a newprocess line in a manufacturing plant, a simple system could be setuplike the above with dozens of low-cost particle counters and one largerunit with a display. The larger unit could be setup to acquire data fromeach of the smaller counters and to display that data either in series(cycling through the counters one at a time), or by using tiles or ascrollable window to allow data from all of the counters to besummarized or displayed. The main counter could also preferentiallydisplay data from the counters, for example in the case of alarms on aparticular sensor its data could rise to the top of a list or appearinstead of or on top of other normal data.

Adding an external vacuum pump, some vacuum hose and power supply wouldmake the system reasonably self-contained. It could be mounted on a cartfor rapid deployment in the case of an event detected in a factoryallowing for quick analysis of a problem, in the hopes of speedyresolution. In many of these installations downtime is very costly, so asystem that can be rapidly deployed and provide quick and effectivemonitoring of dozens or more nodes is of value.

Though not shown, the external counters could be a variety of differenttypes of counters, of classes of counters with varying functionality,sensitivity, or number of channels from a single manufacturer or frommany manufacturers. The main counter would know how to interface to eachof these and how to display the data particular to any one counter(which also providing summary data common to all counters, as in numberof counts for each installed channel, and the size of each channel).

It will be apparent that various aspects of the invention as related tocertain embodiments may be implemented in software, hardware,application logic, or a combination of software, hardware, andapplication logic. The software, application logic and/or hardware mayreside on a server, an electronic device, or be a service. If desired,part of the software, application logic and/or hardware may reside on anelectronic device and part of the software, application logic and/orhardware may reside on a remote location, such as server.

In accordance with the teaching of the invention and certainembodiments, a program or code may be noted as running on a computingdevice, instrument, or unit. The computing device is an article ofmanufacture. Examples of an article of manufacture include: aninstrument, a unit, a server, a mainframe computer, a mobile telephone,a multimedia-enabled smartphone, a tablet computer, a personal digitalassistant, a personal computer, a laptop, or other special purposecomputer each having one or more processors (e.g., a controller, aCentral Processing Unit (CPU), a Graphical Processing Unit (GPU), or amicroprocessor) that is configured to execute a computer readableprogram code (e.g., an algorithm, hardware, firmware, and/or software)to receive data, transmit data, store data, or perform methods. Thearticle of manufacture (e.g., computing device) includes memory that canbe volatile or non-volatile. The memory, according to one aspect, is anon-transitory computer readable medium having a series of instructions,such as computer readable program steps encoded therein.

In accordance with aspects and certain embodiments of the invention, thenon-transitory computer readable medium includes one or more datarepositories. The non-transitory computer readable medium includescorresponding computer readable program code and may include one or moredata repositories. Processors access the computer readable program codeencoded on the corresponding non-transitory computer readable mediumsand execute one or more corresponding instructions.

Other hardware and software components and structures are alsocontemplated. Unless defined otherwise, all technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which this invention belongs. Although anymethods and materials similar or equivalent to those described hereincan also be used in the practice or testing of the invention,representative illustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or system in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the invention is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dateswhich may need to be independently confirmed.

All statements herein reciting principles, aspects, and embodiments ofthe invention as well as specific examples thereof, are intended toencompass both structural and functional equivalents thereof.Additionally, it is intended that such equivalents include bothcurrently known equivalents and equivalents developed in the future,i.e., any elements developed that perform the same function, regardlessof structure. The scope of the invention, therefore, is not intended tobe limited to the exemplary embodiments shown and described herein.Rather, the scope and spirit of invention is embodied by the appendedclaims.

The invention claimed is:
 1. A particle counting system comprising: amemory that stores particle count data and pulse height data; a lightdetecting particle sensor device in communication with the memory, thelight detecting particle sensor device being configured to detectairborne particles and further including a first output channel and asecond output channel, a light detecting particle sensor devicegenerating an electrical signal for each particle counted of a pluralityof particles passing through a light detecting particle sensor device,wherein each electrical signal includes at least a pulse having a peakpulse height; and a signal processing circuit connected to the lightdetecting particle sensor device and the memory, the signal processingcircuit generating digitized pulse height data wherein the pulse heightdata exceeds a first configurable threshold for the first output channeland a second configurable threshold for the second output channel, suchthat each configurable threshold sets a respective minimum peak pulseheight threshold, wherein the memory receives the peak pulse height datafor data storage, and wherein the peak pulse height data above the firstconfigurable threshold for the first output channel is logged to thememory for storage and the peak pulse height data above the secondconfigurable threshold for the second output channel is logged to thememory for storage.
 2. The system in claim 1, wherein at least arrivaltime of each pulse is logged.
 3. The system in claim 1, wherein at leastthe peak pulse height of the pulse associated with each detectedparticle is logged.
 4. The system in claim 1, wherein at least a peakpulse width of the pulse is logged.
 5. The system in claim 1, wherein atleast a pulse area, calculated as a measure of the peak pulse heightmultiplied by a peak pulse width, is logged.
 6. The system in claim 1,wherein logged pulse data is later retrieved to display pulses arrivingover time.
 7. The system in claim 6, where logged pulse data is laterretrieved for performing analysis.
 8. The system of claim 1 wherein thesignal processing circuit further comprises an analog to digitalconverter and a processor that is configured to compute a particle massfor each channel.
 9. The system of claim 1 wherein the signal processingcircuit further comprises a processor that is configured to compute atotal particle mass for a plurality of channels during a time period.10. The system of claim 1 further comprising a controller connected tothe signal processing circuit and the memory, the controller configuredto set a threshold.
 11. The system of claim 1 further comprising abattery and a display, the battery providing power to the displaywherein the display graphically depicts particle count data for eachoutput channel.
 12. The system of claim 1 further comprising a powercontroller that controls power distribution to the system from abattery.
 13. The system of claim 12 wherein the power controller has apower save mode.
 14. The system of claim 1 wherein the system comprisesa link to a network including a plurality of light detecting particlesensor devices that are connected to a data storage device with thenetwork.
 15. The system of claim 1 wherein the light detecting particlesensor device comprises a photodetector that detects particles passingthrough a light beam.
 16. The system of claim 15 wherein the light beamis generated by a laser.
 17. The system of claim 1 further comprising apulse log buffer that stores a pulse height, a pulse width, an arrivaltime and increments a counter.
 18. The system of claim 1 furthercomprising a pump providing an airflow through the light detectingparticle sensor device.
 19. The system of claim 1 wherein the memory isconfigured to store a particle area for each detected particle above theminimum peak pulse height threshold.
 20. The system of claim 1 furthercomprising a plurality of at least three output channels, each channelprocessing particle data for a different particle size range.
 21. Thesystem of claim 1 wherein the light detecting particle sensor devicecomprises a light detector that is connected to an amplifier, acomparator and a peak detector.
 22. The system of claim 1 wherein eachparticle counted is recorded with a time stamped data field.
 23. Thesystem of claim 22 wherein the data field includes a particle pulseheight, a tag and a text field.
 24. The system of claim 1 wherein thesignal processing circuit is connected to a controller to control aplurality of at least three particle counting channels, each channelhaving a threshold configured by the controller and being latched attime intervals simultaneously.
 25. The system of claim 1 wherein thesignal processing circuit comprises a processor is configured to operatea graphical interface on a system display, wherein graphical data can bedisplayed as a function of time.